1. Field of the Invention
The present invention relates to disk drives. More particularly, the present invention relates to disk drives having a head disk assembly including an integrated hinge and methods for manufacturing such disk drives.
2. Description of the Prior Art
A typical hard disk drive includes a head disk assembly (xe2x80x9cHDAxe2x80x9d) and a printed circuit board assembly (xe2x80x9cPCBAxe2x80x9d). The HDA includes at least one magnetic disk (xe2x80x9cdiskxe2x80x9d), a spindle motor for rotating the disk, and a head stack assembly (xe2x80x9cHSAxe2x80x9d) that includes a head with at least one transducer for reading and writing data. The HSA is controllably positioned by a servo system in order to read or write information from or to particular tracks on the disk. The typical HSA has three primary portions: (1) an actuator assembly that moves in response to the servo control system; (2) a head gimbal assembly (xe2x80x9cHGAxe2x80x9d) that extends from the actuator assembly and biases the head toward the disk; and (3) a flex cable assembly that provides an electrical interconnect with minimal constraint on movement.
A typical HGA includes a load beam, a gimbal attached to an end of the load beam, and a head attached to the gimbal. The load beam has a spring function that provides a xe2x80x9cgram loadxe2x80x9d biasing force and a hinge function that permits the head to follow the surface contour of the spinning disk. The load beam has an actuator end that connects to the actuator arm and a gimbal end that connects to the gimbal that carries the head and transmits the gram load biasing force to the head to xe2x80x9cloadxe2x80x9d the head against the disk. A rapidly spinning disk develops a laminar airflow above its surface that lifts the head away from the disk in opposition to the gram load biasing force. The head is said to be xe2x80x9cflyingxe2x80x9d over the disk when in this state.
Within the HDA, the spindle motor rotates the disk or disks, which are the media to and from which the data signals are transmitted via the head on the gimbal attached to the load beam. The transfer rate of the data signals is a function of rotational speed of the spindle motor; the faster the rotational speed, the higher the transfer rate. A spindle motor is essentially an electro-magnetic device in which the electro-magnetic poles of a stator are switched on and off in a given sequence to drive a hub or a shaft in rotation, the hub including a permanent magnetic ring.
FIG. 1 shows the principal components of a magnetic disk drive 100 constructed in accordance with the prior art. With reference to FIG. 1, the disk drive 100 is an Integrated Drive Electronics (IDE) drive comprising a HDA 144 and a PCBA 114. The HDA 144 includes a base 116 and a separate, discrete cover 117 attached to the base 116 that collectively house a disk stack 123 that includes a plurality of magnetic disks (of which only a first disk 111 and a second disk 112 are shown in FIG. 1), a spindle motor 113 attached to the base 116 for rotating the disk stack 123, an HSA 120, and a pivot bearing cartridge 184 (such as a stainless steel pivot bearing cartridge, for example) that rotatably supports the HSA 120 on the base 116. The base 116 is typically attached to the separate cover 117 by means of screws or other discrete fasteners. The spindle motor 113 rotates the disk stack 123 at a constant angular velocity about a spindle motor rotation axis 175. The HSA 120 comprises a swing-type or rotary actuator assembly 130, at least one HGA 110, and a flex circuit cable assembly 180. The rotary actuator assembly 130 includes a body portion 140, at least one actuator arm 160 cantilevered from the body portion 140, and a coil portion 150 cantilevered from the body portion 140 in an opposite direction from the actuator arm 160. The actuator arm 160 supports the HGA 110 with a head. The flex cable assembly 180 includes a flex circuit cable and a flex clamp 159. The HSA 120 is pivotally secured to the base 116 via the pivot-bearing cartridge 184 so that the head at the distal end of the HGA 110 may be moved over a recording surface of the disks 111, 112. The pivot-bearing cartridge 184 enables the HSA 120 to pivot about a pivot axis, shown in FIG. 1 at reference numeral 182. The storage capacity of the HDA 111 may be increased by including additional disks in the disk stack 123 and by an HSA 120 having a vertical stack of HGAs 110 supported by multiple actuator arms 160.
Current trends appear to favor ever-smaller drives for use in a wide variety of devices, such as digital cameras, digital video cameras and other audio-visual (AV) equipment and portable computing devices, for example. Concurrently, the highly competitive nature of the disk drive industry and the ever more stringent size constraints are driving disk drive manufacturers to finds ways to minimize costs. Simplifying the manufacturing process is one avenue that disk drive manufacturers are exploring, with the rationale that fewer manufacturing steps lead to a less costly drive. Toward that end, attention has turned to the drive enclosure as one possible candidate for further cost reductions. Indeed, it has been determined that an HDA configuration wherein the enclosure includes a base and a separate, discrete cover attached with screws might not be optimal, with respect to materials, cost and the number of manufacturing steps required to assemble the enclosure.
What are needed, therefore, are alternatives to disk drives having an HDA enclosure that includes separate base and cover. What are also needed are alternative methods of making hard drives that reduce manufacturing steps and cost.
Accordingly, this invention may be regarded as a disk drive that includes an enclosure defining an exterior surface, the enclosure including a base; a cover; and a hinge mechanically coupling the base to the cover such that the hinge forms a portion of the exterior surface of the enclosure. A spindle motor is attached to the base, a disk is mounted to the spindle motor and a head stack assembly is pivotally coupled to the base.
The base, the cover and the hinge of the enclosure may be unitarily molded to form a single-piece enclosure. The base, the cover and the hinge of the enclosure may be injection molded together. The enclosure, for example, may include or be formed of a plastic material. The plastic material may include or incorporate a non-plastic filler. The non-plastic filler may include a conductive material. The plastic material may include a filler having an electro-magnetic shielding characteristic. At least a portion of the base may include a metal. The base and/or the cover may include a non-plastic material and the hinge may be insert molded onto the base and the cover. The non-plastic material may include a metal. The base may be formed of a metal and the cover and the hinge may be unitarily formed and the unitarily formed cover and hinge may be insert molded onto the base.
The hinge may be formed in a configuration wherein the cover is initially oriented at about 45 degrees relative to the base. The hinge may be formed of a same material as the cover and the base. The hinge may include a hinge bead, the hinge bead being external to an internal space of the disk drive formed when the enclosure is closed. The cover may form a lip over the base when the enclosure is closed.
The present invention, according to one embodiment thereof, is also a method of manufacturing a disk drive, comprising a single molding step to form an enclosure including a base, a cover and a hinge mechanically coupling the base to the cover such that the hinge forms a portion of an exterior surface of the enclosure; attaching a spindle motor to the base; mounting a disk to the spindle motor, and pivotally coupling a head stack assembly pivotally to the base. The molding step may be or include an injection-molding step.
According to another embodiment thereof, the present invention is a method of manufacturing a disk drive, comprising steps of providing a base; providing a cover; molding a hinge onto the base and the cover to mechanically couple the base to the cover such that the hinge forms a portion of an exterior surface of the enclosure; attaching a spindle motor to the base; mounting a disk to the spindle motor, and pivotally coupling a head stack assembly pivotally to the base. The molding step may be or include an insert-molding step.
The foregoing and other features of the invention are described in detail below and set forth in the appended claims.